1. Field of the Invention
The present invention relates to a paired electrical cable and a connector for the pair electrical cable.
2. Related Art
A recent motor vehicle has various kinds of electronic instruments so that the vehicle is arranged with wiring harnesses for transmitting various signals and power to the electronic instruments of the vehicle. The wiring harness has a plurality of electrical cables and connectors joined to ends of the electrical cables for supplying various signals and power to the electronic instruments.
For supplying various signals and power to the electronic instruments, there is provided a paired electrical cable consisting of two cables. One of the electrical cables transmits a signal and the other electrical cable transmits another signal which is opposite in phase. The paired cable decreases noise generated in the cables.
Some motor vehicles have an optional electrical instrument according to a request of a user. This requires supplying additional power and signals to the optional instrument. Thus, new cables are prepared for electrical connection with wiring harnesses having been arranged in the vehicles for transmitting power and signals for the optional instrument. For this purpose, conventional connectors have been utilized.
The electrical cables tend to be received in a narrow space within the vehicle. That is, it is required that a paired cable used for electrical connection of the optical instrument is connected to one of the wiring harnesses within a very narrow space of the vehicle. Such paired cable needs to be connected to another paired cable of the wiring harness such that the signals transmitted through two cables constituting the paired cable are opposite in phase to each other. Thus, the connection of the paired cable to the wiring harness within the narrow space has been a troublesome work.
For correct connection of two of the paired cables, each electrical cable need to be distinguished from each other. Conventionally, a mark or a color is provided on the cables for the distinction thereof.
Furthermore, a recent motor vehicle tends to have an increased number of electronic instruments according to users"" requests, which increases the number of electrical cables constituting a wiring harness and increases the weight of the wiring harness. Therefore, it has been desired that electrical cables have smaller diameters or sizes to transmit various signals for enabling a wiring harness smaller in size or lighter in weight. However, a smaller diameter paired electrical cable is disadvantageous for recognizing a distinction mark or color for electrical connection thereof in a desired pattern.
In view of the aforementioned disadvantage, an object of the invention is to provide a paired cable and an electrical connector for connection of such paired electrical cable with ease. Another object of the invention is to provide a paired electrical cable, in which each of the cables constituting the paired electrical cable can be distinguished from the other with ease.
For achieving the object, an aspect of the present invention is an electrical connector having a pair of first and second terminal fittings each connected to each of a pair of first and second electrical cables and a connector housing holding the terminal fittings, wherein the electrical connector comprises a cable distinction device disposed in the connector housing to guide the first and second electrical cables for electrically connecting the first electrical cable exclusively to the first terminal fitting and the second electrical cable exclusively to the second terminal fitting.
Thus, the cable distinction device guides the pair of cables for surely connecting the first electrical cable to the first terminal fitting and the second electrical cable to the second terminal fitting. This prevents incorrect connection between the cables and the terminal fittings and allows an electrical connection work in a blind space.
Preferably, the cable distinction device has a cutout with a shoulder, the cutout allowing insertion of the electrical cables into the connector housing, the shoulder positioned at a middle of an inner length of the cutout, and the shoulder prevents the first electrical cable from advancing over the shoulder but allows the second electrical cable to advance over the shoulder.
Thus, the insertion of the pair of first and second electrical cables into the cutout of the connector housing allows correct connection to the first or second terminal fittings.
Preferably, the first and second electrical cables have an outer diameter equal to each other, and the first electrical cable has a protrusion projecting from an outer surface of a sheath of the first electrical cable to abut against the shoulder of the cutout when inserted into the cutout.
The protrusion of the first cable abuts against the shoulder of the cutout when inserted into the cutout, allowing the correct insertion of the first and second cables in the positioning of the cables in the connector housing.
Alternatively, the first electrical cable has an outer diameter larger than that of the second electrical cable, and the first electrical cable abuts against the shoulder of the cutout when inserted in to the cutout.
The first electrical cable having the larger diameter abuts against the shoulder of the cutout, allowing the correct insertion of the first and second cables in the positioning of the cables in the connector housing.
Preferably, the electrical connector further comprises a cable receiving space and a second cable distinction device, the cable receiving space receiving a pair of third and fourth electrical cables for electrically connecting respectively to one of the first and second electrical cables, and the second cable distinction device allows the third electrical cable to electrically connect to the first electrical cable but prevents the third electrical cable from electrically connecting to the second electrical cable.
Thus, the third and fourth electrical cables are correctly connected to the first and second electrical cable. This is, the third electrical cable is surely electrically connected to the first electrical cable, while the fourth electrical cable is surely connected to the second electrical cable.
Preferably, the second cable distinction device has a pair of cable receiving chambers with a pair of projections oriented inward in the cable receiving chambers, and the cable receiving chambers receive the third and fourth electrical cables, one of the projections allowing insertion of the third electrical cable and preventing insertion of the fourth electrical cable into one of the cable receiving chambers, the other of the projections allowing insertion of the fourth electrical cable and preventing insertion of the third electrical cable into the other of the cable receiving chambers.
The one of the cable receiving chambers receives the third electrical cable while the other of the cable receiving chambers receives the fourth electrical cable. Thus, the third electrical cable is surely electrically connected to the first electrical cable, while the fourth electrical cable is surely electrically connected to the second electrical cable.
Preferably, the third and fourth electrical cables have an outer diameter equal to each other, and the third electrical cable has a second protrusion projecting from an outer surface of a sheath thereof to abut against one of the projections when third electrical cable is inserted into one of the cable receiving chambers.
The third electrical cable has the second protrusion projecting to abut against one of the projections. Thus, the third electrical cable is surely electrically connected to the first electrical cable, while the fourth electrical cable is surely electrically connected to the second electrical cable.
Preferably, the third electrical cable has an outer diameter larger than that of the fourth electrical cable, and the third electrical cable abuts against one of the projections.
The third and fourth electrical cables are selectively received in the cable receiving chamber since the third electrical cable abuts against one of the projections.
The pair of first and second electrical cables are parallel to each other, and the first electrical cable is different from the second electrical cable in a sectional profile for easy distinction of each of the cables from the other.
The first electrical cable may have a main part with a round section and a protrusion formed on an outer surface of the main part, and the second electrical cable has a round section.
The first electrical cable may have a main part with a round section and a projection formed on an outer surface of the main part, and the second electrical cable may have a main part with a round section and a groove formed on an outer surface of the main part of the second electrical cable.
The protrusion may be extended all over a length of the first electrical cable in a longitudinal direction of the first electrical cable.
Alternatively, the protrusion may be annularly extended on the outer surface of the first electrical cable in a lateral direction of the first electrical cable.
The first electrical cable may have a round section, and the second electrical cable may have a polygon section.